Inosine derivatives

ABSTRACT

Complexes are formed in inosine and aminoalcohols of the formula   WHERE R1 and R2 are lower alkyl and n is an integer of 2 to 4. The complexes have pharmacological activity including the ability to restore deteriorated learning and memory behavior. The preferred aminoalcohol is dimethylamino isopropanol. The preferred ratio of inosine to aminoalcohol is 1:3.

United States Patent Q 191 Gordon Dec. 31, 1974 INOSINE DERIVATIVES 4Primary Examiner-Elbert L. Roberts 5 I P h ll [7 1 nvenlor Gordon Clcago l Attorney, Agent, or FzrmCuShman, Darby & [73] Assignee: NewportPharmaceuticals, Inc., Cushman v Newport Beach, Calif. 22 Filed: Dec. 7,1972 [57] ABSTRACT Complexes are formed in inosine and aminoalcohols [2l] NO.I r of the formula Related U.S. Application Data [62] Division ofSer. No. 145,929, May 2l, 1971, which is a division of Ser. No. 853,864,Aug. 28,1969, Pat. n zn) No. 3,646,007. I

[52] U.S. Cl. 424/180, 260/211.5 [51] Int. Cl. A01n 9/00, AOln 9/28where 1 and 2 are lower alkyl and n is aninteger of [58} Field of Search.J. 424/180; 260/211.5 2 to The complexes have pharmacological ivity I sincluding the ability to restore deteriorated learning [56] ReferencesCited and memory behavior. The preferred aminoalcohol is UNTED STATESPATENTS dimethylamino isopropanol, The preferred ratio of 3,520,8737/1970 Thiel er al 260/21 1.5 "105mm ammoalcoho] 3,728,450 4/1973 Gordon424/180 9 Claims, 3 Drawing Figures g 80 u E 4'0 n l r A A s l 1 l l \fm r N l l v U w/ \l 6 5- .9 l0 1 l2 l5 W/f/f az/ravw m mac/vs) INOSINEDERIVATIVES This is a division of application Ser. No. 145,929, filedMay 21, 197i, which is a division of application Ser. No. 853,864, filedAug. 28, I969, now US. Pat. No. 3,646,007, issued Feb. 29, 1972.

The present invention relates to novel inosine derivatives.

lnsoine is a ribosideknown to have physiological activity, e.g., seeInosine" published by Morishita Pharmaceutical Co., Ltd. of Osaka, Japanand-also Metabolic Activator lnosine Preparations" published byMorishita Pharmaceutical Co., Ltd.

lnsoine, however, has lesser learning enhancement properties than thecomplex of the present invention in agedanimals and in some situationswhere the complex of the present invention enhances learning, inosineactually retards learning.

It is an object of the present invention to develop novel inosinederivatives.

Another object is to restore deteriorated learning ability.

An additional object isto reduce senility and reduce agingcharacteristics,

A further object is to combat viral diseases.

Still further objects and the entire scope of applicability of thepresent invention will become apparent from the detailed descriptiongiven hereinafter; it should be understood, however, that the detaileddescription and specific example, while indicating pre-' ferredembodiments of the invention, are given by way of illustration only,since various changes and modifications within the spirit and scope ofthe invention will become apparent to those skilled in the art from thisdetailed description.

It has now been found that these objects can be attained by makingcomplexes of inosine with dialkylamino alkanols. The complexes can beused in the form of the free base or in the form of their salts withpharmacologically acceptable acids.

While the uses are primarily in the pharmacological area, the salts areuseful as curing agents'for melamineformaldehyde or urea-formaldehyderesins.

The dialkylamino alkanols preferably have the formula where R and R arelower alkyl, e.g. methyl to butyl, and n and n is an integer of 2 to 4.Typical inosine complexes include the complexes with dimethylaminoethanol, dimothylamino isopropanol, diethylamino ethanol, diethylaminoisopropanol, methyl ethyl amino ethanol, dimethylamino propanol,dimethylaminobutanol, dibutylamino ethanol, dipropyl aminoethanol,diisopropylamino ethanol. The preferred aminoalcohol compound isdimethylamino isopropanol since'it exhibits the widest variety ofproperties.

As acids for forming the salts any pharmacologically acceptable acidscan be used such as hydrochloric acid, sulfuric acid, phosphoric acid,acetyl salicylic acid, dtartaric acid, maleic acid, fumaric acid,succinic acid, citric acid, trans cinnamic acid, salicylic acid, adipicacid, methane sulfonic acid, acetic acid, paminobenzoic acid, propionicacid. Most of the salts with the amines are hygroscopic. However, thepacetamidobenzoic acid salt of the inosinedimethylamino isopropanolcomplex is a solid and is the presently preferred salt. It is preparedby mixing dimethylaminoisopropanol and p-acetamido benzoic acid mole formole and then heating slightly. The salt thus formed is then dry mixedwith inosine in a mole ratio of, for example, either lzl or 3:1 (salt toinosine). The complex is then formed, for example, by dissolving inwater and can be .recovered therefrom if desired by evaporation.

The mole ratio of aminoalcohol to inosine can vary from 111 up to 10:1.The preferred ratio is 3:1 (aminoalcohol to inosine).

According. to the present invention unique pharmacological properties ofN,N-dialkyl alkanolamine derivatives have been discovered which arepertinent to overcoming learning defects, reducing or eliminatingsenility, aid in the treatment of neuroatrophic diseases,

e.g., amyotrophic laterial sclerosis (ALS) and other conditions in whichthe synthesis of large molecular weight ribonucleic acid (RNA) andproteins in the brain may be inadequate. I

The compounds, and particularly the dimethylamino isopropanol complex ofinosine, (mole ratio 1:1 to 10:1. preferably 3:1), have been found to(l) restore the deteriorate d learning and memory behavior of aged ratsto the young normal state for both difficult and easy tasks at all timesof the day and night and (2) to enhance the capacity of young rats tolearn very difficult tasks. The effect is unique as inosine or theaminoalcohols alone never produce the effects in question as intenselyas the combination and, in fact, for young animals at certain times ofthe day, actually produce a learning impairment while in contrastthecombination of the present invention produces an enhancement oflearning.

The compounds of the present invention when the molar ratio ofaminoalcohol to inosine is from 1:1 to 3:1 have an LD in excess of 4,000mg/kg in rats or mice when fed either intraporitonsally orally. Above a10:1 aminoalcohol to inosine ratio there is a significant increase intoxicity.

It appears that the use of theaminoalcohols with inosine to form thecomplexes of the present invention modifies the metabolism of inosine inthe brain. Thus, when one of the complexes (from dimethylaminoisopropanol and radioactive inosine) was injected into the brain of arat the metabolism of the radioactive inosine was altered radically(radioactive inosine was used as a tracer.)

While inosine. has some enhancing effect on the memory and learning ofaged animals, e.g., rats and mice, the inosine-aminoalcohol complexes ofthe present invention (particularly the dimethylamino isopropanolcomplex, e.g., 1:1 molar ratio) have a greater effect.

In middle aged or young animals (rats) where inosine inhibited learningthe complex of the present invention, on the contrary, enhancedlearning. The difference in effect was dependent on the time of day. Inthe evening both the inosine and the complex [dimethylamino iso propanolcomplex (lzl molar)]enhanced the learning. A't earlier times of the day,e.g., morning orearly afternoon, only the complex enhanced learning.

The learning enhancement effects are best seen when the task used willbring outthe deteriorated. characteristics present in aged animals. Ineasy tasks which the aged animals can accomplish as well as the young,the inosine or the inosine aminoalcohol complex enhance learning only inthe evening. With more difficult tasks, the complex (1:1 molar) enhanceslearning in the daytime while inosine itself inhibits learning.

At night when the animals (rats) are active, the complex (1:1 molar) issignificantly better than inosine imparting learning enhancement on bothvery difficult and middingly difficult tasks. In the morning withdifficult tasks, the complex enhances learning while inosine inhibitslearning.

With other drugs, it has been established by those skilled in the artthat there is a correlation between learning enhancement in othermammals, e.g., rats, and in humans.

The inosine diethylamino isopropanol complex (1:1 molar) makesindistinguishable the learning and memory of young rats and old rats inwhom learning and memory was defective in the absence of treatment. Theresults are much more dramatic than has been found with diphenylhydantoin.

It has also been observed that the inosine complex of I the invention[e.g., 1:1 molar or 1:3 molar (inosine to aminoalcohol)]modify thepolyribosomes, making them more internally hydrogen bonded. The complexdoes this to a greater extent than inosine-and inosine does this to agreater extent than does blank controls.

Furthermore, in tests on rats, it has been found that the when all ofthe controls died. It has further been found that the complex (1:1 or3:1 molar aminoalcohol to inosine) can be administered up to 12 hoursafter inoculation with the virus whereas in 15 minutes infection willset it.

When inosine and dimethylamino isopropanol were placed in aqueoussolution and evaporated to dryness, there was obtained first aprecipitate of pure inosine and then the complex as a residue having adifferent IR spectrum. The molar ratio of aminoalcohol to inosine was3:1.

Inosine and excess dimethylamino isopropanol hydrochloride were mixedand fused. An attempt was made to sublime off the excess amine. Not allof the amine could be recovered by sublimation. The residue had 3 aminogroups per inosine group.

When inosine and dimethylamino isopropanol were dissolved in water inthe molar ratio of 1:10 (inosine to aminoalcohol) the ultravioletspectroscopy showed a unique spectrum, not merely an additive effect.Thus at 285 millimicrons, there was a unique UV peak and a negative peakat 200 millimicrons.

Evidence of the novelty of the complex is shown in the drawings whichare the IR (infrared) curves for three compounds in the range of 6 to 13microns.

FIG. 1 is the IR spectrum for the complex of 1 mole of inosine with 4moles of dimethylaminoisopropanol hydrochloride dissolved in waterfollowed by drying.

FIG. 2 is the IR spectrum for inosine, and

FIG. 3 is the IR curve for a dry physical mixture of inosine anddimethylaminoisopropanol hydrochloride (1:1 molar).

A comparison of the curves makes it evident that the complex (FIG. 1)has a different IR spectrum or curve then would be expected from itscomponents. Thus the expected peaks at above 11.45 microns, at 8microns, at 8.1 microns and at 8.55 microns are missing in FIG. 1 butare present in FIGS. 2 and 3.

With mole ratios of inosine to aminoalcohol, e.g. dimethylaminoisopropanol, of as little as 1:10 a difference in ultraviolet (UV)spectroscopy was noted over that to be expected from the constituents.

When inosine and dimethylamino isopropanol were mixed in distilled waterUV spectra were observed which reveal the existence of unique electronstates giving evidence of complex formation. Thus, there was studied thespectrum of aqueous solution 0.5 molar in dimethylamino isopropanol and0.022 molar in inosino at a. pH of 10.0 (using a 0.5 molar N HPO KOHbuffer) and it was compared with the spectrum in the absence of inosine.Short wavelength energy was found to disappear and longer wavelengthenergy to appear in the presence of the inosine. This shift towardslonger wavelength observance was associated with the appearance of a newpeak at about 270 millimicrons.

At a pH of 7.2 an aqueous solution 0.5 molar in dimethylaminoisopropanol and 0.037 molar in inosine showed a similar but weakerreaction. Minor pH adjustments were made to the inosine solutionemploying minute quantities of NaOH; the dimethylamino isopropanol wastitrated with HCl to the pH value of 7.2 and was thus in the form of thehydrochloride salt The new peak occurred at about 285 millimicrons(rather than at 270 millimicrons).

A variety of ratios of inosine to dimethylamino isopropanol were studiedat both a pH of 10.0 and 7.2 with qualitatively similar results. Thesystem was also studied in the presence and absence of 0.5 molar HCl,added to the inosine solution without dimethalimino isopropanol withoutsignificant change in results, indicating that the spectral differencesobserved were not a function of the presence of chloride or non-specificcations. It has been observed that dimethylamino isopropanol and inosinetogether in an aqueous medium generate UV absorption spectra inalkaline, neutral and acid pH ranges which depart from the sum'of thespectra of the solutes taken separately in such a way as to revealcomplex formation.

On the other hand, it has also been noted that there is a disappearanceof a peak at about 200 millimicrons at a pH of 7 when using an aqueoussolution of inosine and dimethylamino isopropanol in the mole ratio of1:10.

The diffusion coefficient of inosine in water was also observed. At a pHof 10.4, the diffusion of inosine into water is about greater than thatof an inosinedimethylamino isopropanol mixture. Furthermore, inosinediffuses more rapidly into an aqueous solution of dimethylamioisopropanol than into water alone. All of the diffusion andspectroscopic properties set forth above indicate that there is a unionof the two components, i.;e., inosine and the aminoalcohols.

The combination of inosine and aminoalcohol, e.g., dimethylaminoisopropanol or dimethylamino ethanol inhibits ribonuclease which neithercomponent can do alone.

It has also been observed that the administration of a solid powdermixture of inosine and the aminoalcohol hydrochloride, e.g.,dimethylamino isopropanol hydrochloride, when put into solution at thetime of administration, had the same effect as the preformed watersolution/The two components of the complex can be administered and thepreformed complex, together or even separately, providing there is anopportunity for the two components to get together in the body of theanimal.

A patient having amyotrophic lateral sclerosis was fed the inosine andeither dimethylamino ethanol or dimethylamino isopropanol. The twocomponents of the complex were administered separately, butsubstantially simultaneously. During the course of the year, sometimesthe dimethylamino ethanol complex and sometimes the dimethylaminoisopropanol complex was used. The patient was treated sometimes everyday and sometimes 3 times a week. The patient who' weighed 130 lbs.received daily dosages of the complex varying mm 80 to 138 mg/kg withouttoxic effect over a period of several months. The inosine was fed bymouth in milk and the aminoalcohol was taken in orange juice.

Dimethylaminopropanol does not have the desired chemicophysicalproperties to nearly the same extent as dimethylamino isopropanol.

The compounds or complexes of the present invention can reduce agingcharacteristics in mammals such as rats, mice, guinea pigs, andprimates, dogs, cats,

- horses, cattle; sheep, and pigs. The complexes, e.g., the

inosine dimethylamino isopropanol complex, can be used in breedinganimals since they reverse deterioration in the liver and the brainfurthermore enhance the brain function.

A definite antiviral action has been observed against RNA (ribonucleicacid) and DNA (desoxyribonucleic acid) viruses including influenza typeA (both the PR strain and the Bethesda strain) in mice aswell as herpesvirus (Lu) in mice In these tests, the inosine and dimethylaminoisopropanol were mixed in aqueous solution in molar ratios varying from1:1 to 1:10 and adjusted to pH 7.0 with HCI. This solution was etherinjected intraperitoneally into mice twice daily at a dose level of 138mg/kg or placed in the water supply such that each animal consumedapproximately 275 mg/kg per day via natural water intake. The inosineDMAIP (dimethylamino isopropanol) combination suppressed morbidity anddeath due to inoculation of influenza or herpes virus. lnosine alone wasineffective against herpes virus and had a minor insignificant effectagainst influenza virus.

Typical results were as follows:

Influenza Virus In mice given influenza virus (A-2 Bethesda strain byintranasal innoculation with treatment begun at 3 hours afterinnoculation, 0 of 59 animals givenplacebo intraperitoneal injections(saline) survived.

Herpes Virus Herpes virus was given intravenously to mice and treatmentbegun after 3 hours, 1 of 59 control animals survived, while 17 or 30animals survived who were vention. If the ratio is reduced to below 1:1,e.g., 1:0.5,

then the so'lutility of the complex in water is reduced.

It is believed that the complexes of the present invention act bychanging the internal structure of biological polymers and polymer-richorganeles in such a way as to render these less inclined to generatepositive entropy or randomness.

This change is important in aging because it has been found thatpolymer-rich organeles in aging tissue tend to generate an abnormalamount of positive entropy, i.e., randomness. The changes produced bythe complexes of the invention render the polymer-rich organeles moreresistant to influences inducing loss in internal hydrogen bonding andhence renders them more resistant to attack by destructive enzymes.

The p-acetamidobenzoate salt of the complex is prepared in a simplemanner by mixing the aminoalcohol, e.g., dimethylamino isopropanol, andpacetamidobenzoic acid in equimolar amount and heating slightly. Thesalt thus produced can be simply mixed with inosine in a mole ratio ofsalt to inosine of 1:1, 3:1, 4:1, etc. and the product is ready to putinto aqueous solution. The aqueous solution can then be evaporated todryness to obtain the complex in solid form. It has been observed withinosine DMAIP pacetamidobenzoate that the solubility increases as themole ratio goes rom 1:1 to 1:2 to 1:3 to 1:4, but that at 1:5 there isno increase in solubility. The inosine- DMAIP p-acetamidobenzoate saltis neutral.

Dimethylamino-2-propanol-p-acetamidobenzoate times with additionalanhydrousethyl ether, dried atroom temperature and recrystallized from100 ml. ab-

solute methanolethyl acetate 25:75 (by volume). This product was driedat 50C under vacuum. Yield 56.5 grams MP. 147148C, Empirical formulaC,.,H O N C 59.54% (Theory 59.50%), H 7.83% (Theory 7.80%), N 10.04%(Theory 9.92%).

The salt was readily soluble in water and'very stable over a wide rangeof atmospheric conditions. It decomposed around 2530C. above its meltingpoint-yielding the free acid quantitatively. By heating at 50C. atnormal pressure the change in weightwas 66 hours 0.227r hours 0.28% 172hours The effect of dimethylamino-Z-propanol (DMAlP) and dimethylamino2-propanol-p acetamido benzoate (DMAIPA) on the water solubility ofinosine is set forth below.

It should be noted that 268 mg. of inosine will dissolve in 159 grams ofDMAlP.

TABLE A inosine DMAlP Volume H O Millimoles Mg. Millimolcs Mg. fordissolution l 268 0 16.75 ml. 1 268 l 103 L ml. 1 268 2 206 0.44 ml. I268 3 309 0.40 ml. 1 268 4 4l2 0.35 ml. 1 268 5 515 0.40 ml. 1 268 6 6l50.47 ml.

TABLE B lnosine DMAlPA Volume 11,0 Millimoles Mg. Millimoles Mg. fordissolution 0 0 l 282 0.14 ml. 1 268 l 282 6.8 ml. 1 268 2 S64 3.5 ml. 1268 3 846 2.8 ml. l 268 4 1128 2.2 ml. 1 268 5 l4l0 2.2 ml. 1 268 6 I6922.2 ml.

All solutions set forth in Tables A and B were made at 23C. In regard toTable B, it should be noted that a small amount of p-acetamidobenzoicacid precipitated when the water was added.

There have been identified unique pharmacological properties inN,N-dialkyl alkanolamine derivatives of inosine of use in correctinglearning defects, suppressing viral infections, overcoming senility,neuroatrophic diseases and other conditions in which the synthesis oflarge molecular weight RNA and proteins in the brain may be inadequateor altered.

Principally, it has been found that the inosineaniinoalcohol complexrestores the deteriorated learning and memory behavior of aged rats tothe young normal state for both difficult and easy tasks at all times ofthe day and night and that the complex enhances the capacity of youngrats to learn very difficult tasks. The effect is unique, as inosine orthe amine alcohols alone never produce the effects in question asintensely as the combination and, in fact, for young animals at certaintimes of the day, inosine or the amino alcohols actually produce alearning impairment, while the combination produced an enhancement.Dramatic changes in the learning behavior of young and old rats wereexamined by application of avoidance learning tasks of gradeddifficulty, as described by Doty [Journal of Gerontology, Vol. 2l, pages287-290 (l966)].

The data below in Table l exemplify effects of theN,N-dimethylaminoethanolcomplex of inosine. These data were gatheredbetween 7 and 9 pm, which is the beginning of the rat day as they arenocturnal animals, and represent the number of successful avoidance (ortask solutions) in 90 trials made by rats of different ages when exposedto a regimen of learning at one of two different levels of taskdifficulty. Thirty trials were given per day, 2 hours following eitherplacebo injection or 100 mg/kg dimethylaminoethanol inosinate complex.This dosage was used in all behavioral studies. These data show that thecomplex enhances the capacity to learn ofboth young and old animals; andthat it brings the deteriorated learning performance of aged animals,especially evident for the difficult tasks, to young normal controllevels. Subjecting these data to a computer analysis of variance, theranking of treatment with regard to their capacity to producelearning-enhancing effects was inosine-amino-alcohol complex inosineplacebo (p 0.00l

Table 2 explores the effects of inosine and inosineN,N-dimethylaminoisopropanol complex on the learning capacity ofmiddle-aged rats (13 months) for difficult tasks examined at 9 a.m.according to the protocol described above. The complex produced asignificantly greater degree of task learning than inosine, and inosineactually impaired learning relative to placebotreated controls, at thistime of day. It is pertinent to this difference in actual sign of effectbetween inosine and the complex in the above animals, examined at 9a.m., that brains from animals treated with these drugs also manifestprobably significant biochemical effects that are opposite in sign; thatis, in the presence of polyribosomes plus cell sap fractions frominosinetreated brains, RNA was destroyed more rapidly than in thecontrol system, while in the presence of such fractions from thecomplex-treated brains, RNA was destroyed more slowly than in thecontrol system.

In another experiment, there was explored effects of inosine and thedimethylaminoisopropanol inosinate complex, on the acquisition andrecall of a very easy task examined at either 9 a.m. or 9 pm. In thiscase, the recall was carried out 10 days after acquisition withoutadditional drug treatment. Criterion here represents achievement of 7successful avoidances out of 10 trials; thus the fewer the number oftrials required to achieve this level of performance, the greater theintelligence of the animal. In addition to learning effect, a study ofspontaneous motor activity was carried out in similar animals given thetreatments studied. The results are set forth in Table 3. It is seenthat in the morning, when given at a time of high spontaneous sleepactivity for rats, the complex actually impairs learning and recall inthe young animals while at the same time significantly reducing thespontaneous motor activity. Such an impairment, in this case, can berelated to a tendency of the drug to reduce spontaneous activity or toincrease the tendency to sleep as the acquisition of simple tasks inrodents is easily interfered with by effects that decrease vigilance. Inthe very aged animals, the spontaneous activity during both the 9 a.m.and the 9 pm. periods are reduced in both control and treatment groupsand are not further reduced by drug. in this animal age group (thetarget population), the inosinedimethylamino isopropanol complexproduces a significant enhancement of both acquisition and recall.

The optimum functioning of the brain or other areas of nervous tissue,especially in situations of learning, adapting or other types of highactivity, is generally considered to require the synthesis of new RNAand protein. The aged brain synthesizes less RNA and protein of theheaviest molecular weight, therefore, deficit states of behavior andnervous system function may exist in which a drug capable ofenhancingthe synthesis of large molecular weight RNA and protein would bespecifically beneficial. in sucrose density gradient polyribosomestudies, the inosine-aminoalcohol complex of the'invention increases therate of synthesis of RNA to a greater degree than inosine. Theinosineaminoalcohol complex was an inhibitor of the enzyme, RNase, whichdestroys RNA. While inosine stimulated this enzyme, inosine increasesthe rate of synthesis of RNA over controls to a significantly smallerdegree than the complex of the invention. Furthermore, the complex, butnot inosine causes the increased appearance of an important particulatebody recently discovered in brain, called the informosome. This is abody identified in its centrifugation characteristics as falling betweenand 60 S, Svedberg units, significantly lighter than ribosome monomers.This body has been held to participate in transport ofinformation-carrying RNA from the nucleus to the cytoplasm, wheremessenger RNA union with ribosomes occurs. The action has been proposedas a means of protecting messenger RNA from premature destruction byRNase. It has been found that the complex ofthe invention identifiedTABLE 2 EFFECT OF lNOSlNE AND lNOSlNE-DlMETHYLAMlNOlSOPROPANOL ON TASKACQUISITION Mean Successes in 90 Trials by All Subjects Testing at 9:00AM.

- Delayed Avoidance Task Treatment N 6 for all groups. 'Significantlylarger than mean for inosine-treated rats (P 0.0l

TABLE 3 EFFECT OF lNOSlNE-DIM ETHYLAMINOISOPROPANOL ON TASK ACQUlSlTlONTrials Run to Achievement of Criterion and Open-Field Activity N 8 forall groups.

'" Significantly different from meanohtairted by saline groups of sameage and test time (P ().0]

Significantly larger than means of saline controls in other age groups(P 0.0S Significantly different from mcan.nhtained hy saline groups ofsame age and test time (P 0.05).

increases the informosome content specifically in aged brain.

TABLE 1 EFFECT OF lNOSlNE AND lNOSlNE-DlMETl-lYLAMlNOETHANOL ON TASKACQUlSlTlON Mean Successes in 90 Trials by All Subjects Testing Between7:00-9:00 PM.

N it for all groups (N is number of animals.)

Significantly larger than mean for same age control rats (P 0.01).

Analysis of variance establishes that the ranking of inosine-DMAEinosine saline for .noidztnces made in trials is significant at P (1.01.

P is the probability value depending on chance alone.

In Table 1, the dimethylaminoethanol inosine complex had a mole ratio of1 to 1. The aqueous solution injected contained 30 mg. of complex per1.0 ml. of water.

In Table 2, the inosine was injected in an amount of 70 mg/kg. bodyweight. The aqueous solution injected containing 20 mg. of inosine'per1.0 m1. of water. The inosine-dimethylamino isopropanol complex had amole ratio of 1 to 1 and was injected in an amount of mg/kg body weight.The aqueous solution injected contained 30 mg. of inosine-dimethylaminoisopropanol complex per 1.0 ml. of water.

In Table 3, the saline was injected in an amount of 8.7 mg. of salt/kg.body weight, the aqueous solution injected containing 8.7 mg. of saltper 1.0 ml. of water. The inosine-dimethylamino isopropanol complex hada mole ratio of 1 to 1 and was injected in an amount of 100 mg/kg. bodyweight. The aqueous solution injected contained 30 mg. ofinosine-dimethylamino isopropanol'complex per 1.0 ml. of water.

The complexes of the present invention can be fed to a mammal in adosage of 1 to 1,000 mg/kg. of body weight.

What is claimed is:

11. A method of improving memory in a mammal comprising feeding themammal a complex of inosine with a dialkylaminoalkanol having theformula:

where R and R are lower alkyl, n is an integer of 2 to 4 and the moleratio of inosine to aminoalkanol is from 1:1 to .l :10, said feedingbeing in an amount sufficient to improve the memory of the animal.

2. A method according to claim 1 wherein the aminoalcohol of the complexis selected from the group consisting of dimethylaminoethanol anddimethylaminoisopropanol.

3. A method according to claim 2 wherein the mole ratio of inosine toaminoalkanol is from 1:1 to 1:4.

4. A method according to claim 3 wherein the com-- plex is fed in anamount of l to 1000 mg/kg body weight of the mammal.

5. A method of improving memory' in a mammal comprising feeding themammal a mixture of inosine and a dialkylaminoalkanol having the formulaare methyl and n is 2.

1. A METHOD OF IMPROVING MEMORY IN A MAMMAL COMPRISING FEEDIG THE MAMMALA COMPLEX OF INOSINE WITH A DIALKYLAMINOALKANOL HAVING THE FORMULA:
 2. Amethod according to claim 1 wherein the aminoalcohol of the complex isselected from the group consisting of dimethylaminoethanol anddimethylaminoisopropanol.
 3. A method according to claim 2 wherein themole ratio of inosine to aminoalkanol is from 1:1 to 1:4.
 4. A methodaccording to claim 3 wherein the complex is fed in an amount of 1 to1000 mg/kg body weight of the mammal.
 5. A method of improving memory ina mammal comprising feeding the mammal a mixture of inosine and adialkylaminoalkanol having the formula
 6. A method according to claim 3wherein the mammal is a rat, mouse, guinea pig, dog, cat, horse, cow,sheep or pig.
 7. A method according to claim 6 wherein the mammal is arat.
 8. A method according to claim 1 wherein R1 and R2 are methyl and nis
 2. 9. A method according to claim 5, wherein R1 and R2 are methyl andn is 2.